Optical spectroscopy and crystal field analysis of Cm3+ in LaCl3

The optical spectrum of the Cm3+ ion diluted in the host crystal LaCl3, has been remeasured using the isotope Cm-248 by absorption, fluorescence, excitation, and excited-slate absorption spectroscopy. Analysis of these spectra resulted in the assignment of 103 energy levels, which were fitted to the parameters of an empirical Hamiltonian with an rms deviation of 15.7 cm(-1). The free ion and crystal field parameters obtained from the empirical fit are consistent with an earlier systematic study of the trivalent actinide ions in this lattice. The lifetimes of the five fluorescent levels have been measured at room and liquid helium temperatures. These lifetimes are analyzed to establish the mechanisms which contribute to the relaxation of the excited Cm3+ ion in this host.